From: Rob Biedenharn <Rob@...>
Date: 2007-02-14T10:25:10+09:00
Subject: Re: Puzzling regex behaviour


On Feb 13, 2007, at 7:13 PM, Ian Macdonald wrote:

> On Wed 14 Feb 2007 at 09:08:17 +0900, David Balmain wrote:
>
>> On 2/14/07, Ian Macdonald <ian@caliban.org> wrote:
>>>
>>> I should have asked by now, but can anyone else reproduce this with
>>> Ruby 1.8.5?
>>
>> I can reproduce this 1.8.4
>
> Just to be clear, you are confirming that the following code:
>
> foo = "pr�f�r�es"
> p foo =~ /[^[:alnum:]]/
>
> prints nil in irb and 2 in a stand-alone script when in both cases  
> your
> locale is preset to nl_NL?
>
> Ian
> -- 
> Ian Macdonald               | On a clear disk you can seek forever.
> ian@caliban.org             |
> http://www.caliban.org/     |

I'm beginning to wonder if the original question is even accurate.   
Doing nothing more than changing the encoding and re-saving the file  
(where the value for foo was a cut-n-paste from the email), there  
doesn't seem to be any discrpeancy between ruby and irb.  (This  
output is from ruby 1.8.5, but 1.8.2 was the same)

rab:code/ruby $ file regexp_and_alnum_versus_w.rb
regexp_and_alnum_versus_w.rb: ISO-8859 text
rab:code/ruby $ cat regexp_and_alnum_versus_w.rb
foo = "pr?f?r?es"
alnum = /[^[:alnum:]]/
dubya = /\W/

puts "foo\n  => #{foo.inspect}"
[ alnum, dubya ].each do |re|
   puts "foo =~ #{re}\n  => #{foo =~ re}"
end
rab:code/ruby $ ruby regexp_and_alnum_versus_w.rb
foo
   => "pr\351f\351r\351es"
foo =~ (?-mix:[^[:alnum:]])
   => 2
foo =~ (?-mix:\W)
   => 2
rab:code/ruby $ irb -r regexp_and_alnum_versus_w.rb
foo
   => "pr\351f\351r\351es"
foo =~ (?-mix:[^[:alnum:]])
   => 2
foo =~ (?-mix:\W)
   => 2
 >> eixt
NameError: undefined local variable or method `eixt' for main:Object
         from (irb):1
 >> exit
rab:code/ruby $ file  
regexp_and_alnum_versus_w.rbregexp_and_alnum_versus_w.rb: UTF-8  
Unicode text
rab:code/ruby $ cat regexp_and_alnum_versus_w.rb
foo = "pr�f�r�es"
alnum = /[^[:alnum:]]/
dubya = /\W/

puts "foo\n  => #{foo.inspect}"
[ alnum, dubya ].each do |re|
   puts "foo =~ #{re}\n  => #{foo =~ re}"
end
rab:code/ruby $ ruby regexp_and_alnum_versus_w.rb
foo
   => "pr\303\251f\303\251r\303\251es"
foo =~ (?-mix:[^[:alnum:]])
   => 2
foo =~ (?-mix:\W)
   => 2
rab:code/ruby $ irb -r regexp_and_alnum_versus_w.rb
foo
   => "pr\303\251f\303\251r\303\251es"
foo =~ (?-mix:[^[:alnum:]])
   => 2
foo =~ (?-mix:\W)
   => 2
 >> exit


-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com